Gas reservoir stress sensitivity and its effect on productivity in Feixianguan of Heba block

Gas reservoir in Feixianguan of Heba block belongs to a fracture-pore-type reservoir with abnormally high pres sure and the formation pressure coefficient is high up to 2.3.During producing process,the productivity dropped quickly,showing some stress sensitivity.Through coring laboratory analysis,such as rock stress sensitivity analysis,differential pressure effect on permeability stress sensitivity analysis and permeability recoverability analysis,the permeability of the gas reservoir is found to be characterized by strong sensitivi ty and a high degree of formation.Besides that,the permea-bility damage rate is high up to 60%.In combination with practical production analysis,the result indicates stress sen sitivity has a good effect on reservoir development and when the formation pressure drops to 20 MPa,the productivity will decrease 66%.Therefore,it is necessary to select a rea sonable drawdown pressure so as to slow down the damage of stress sensitivity to reservoir permeability and reservoir productivity,and finally ensure the gas reservoir is under reasonable drawdown pressure and reasonable production status.